Hermetically encapsulated refrigerant compressor

ABSTRACT

The invention relates to a hermetically encapsulated refrigerant compressor comprising a housing having a bottom part and a cover, the cover being connectable to the bottom part, an electrical connection piece penetrating the housing and a piston pump which is arranged in the housing and can be electrically connected to a control unit via the connection piece. The cover of the housing has a through opening in which the electrical connection piece is arranged. The housing is configured in such a way that, when the housing is open, the piston pump can be inserted into the cover of the housing and is connectable to the electrical connection piece.

The present invention generally relates to hermetically encapsulated refrigerant compressors of the reciprocating compressor type, and in particular to such compressors for refrigerating machines used in household appliances such as refrigerators, freezers and small air conditioners.

Furthermore, the invention relates to a method of assembling such a refrigerant compressor.

In the development of refrigerant compressors, a strong trend towards keeping the dimensions of these compressors, in particular their height, as low as possible becomes apparent. The reasons for this trend are manifold. For example, the compartment for the refrigerant compressor in a refrigerator or, respectively, a freezer can have a smaller design, whereby a larger usable volume can be obtained with the unit size of the refrigerator or freezer staying the same. In line with this trend, the housing of the refrigerant compressor must inevitably become more and more compact, with the aim being a shape of the compressor housing which, for structural/mechanical reasons, is similar to a sphere as much as possible. In known compressor housings, an electrical connection piece is generally arranged on the bottom part of the compressor housing, which serves the purpose of electrically connecting the piston pump to a control unit. Due to the requirement to keep the compressor housing as small as possible, manufacturers of refrigerant compressors of the above type move the connection piece further and further towards the base on which the refrigerant compressor is placed. This can lead to major problems in terms of installation technology, since the aforementioned electrical connection is generally implemented by a standardized electrical plug-in connection, the dimension of which is specified by standards and therefore is not variable. If the connection piece, which is usually designed as a plug of a plug-in connection, is electrically connected to a corresponding socket, this can lead to the result that the plug-in connection lies in an undesirable manner on the base on which the refrigerant compressor is to be placed and fastened when the refrigerant compressor is being installed or that, in the event that the electrical connection is made only after the refrigerant compressor has been installed, the socket can be connected to the plug only with difficulty because of the small installation space that is available. Besides an unsteady footing of the refrigerant compressor, this may cause damage to the plug-in connection and/or the electrical connection between the piston pump and the control unit, especially if a cable line leading away from/to the plug-in connection is sandwiched between the plug-in connection and the base.

For the above-mentioned reasons, in current refrigerant compressors, the control unit is arranged essentially at the same level as the bottom part of the compressor housing. However, this results in further disadvantages in terms of installation technology, since the installation space for the refrigerant compressor often has a very small and narrow design. In addition, the above-indicated arrangement of the refrigerant compressor and the control unit reduces the installation space, which may hamper and prolong the assembly and installation of the refrigerant compressor in a refrigerator, for example.

Another significant disadvantage of current refrigerant compressors is that their housings have to be larger than what would actually be required for the installation of the compressor components in the housing because of the arrangement of the connection piece with the above-described problems, whereby the usable volume of the refrigerator or, respectively, the freezer is, in turn, reduced.

DE 37 13 893 A1 discloses a hermetic enclosure for refrigerant compressors which comprises a bottom part and a top part, which are identical drawn parts each having one shoulder. In the shoulder of the top part, a through opening is formed in which electrical connections are arranged. Through holes with connections associated with refrigeration technology are formed in the shoulder of the bottom part. The arrangement of the connections associated with refrigeration technology in the bottom part indicates that, during assembly, the compressor block is inserted into the bottom part and connected to the connections associated with refrigeration technology. Furthermore, it is noted that the compressor block is conventionally suspended resiliently in the bottom part.

DE 24 13 036 discloses a hermetically sealed capsule composed of two horizontally divided capsule halves. A current feedthrough is arranged in the axis of the upper half of the capsule. By means of helical springs, a motor-compressor unit is elastically suspended on supports on the lower half of the capsule. The motor-compressor unit is used during the assembly with the supports and the helical springs in the lower half of the capsule. It is evident from the figures that the motor-compressor unit is connected to the upper half of the capsule only via a cable.

In current reciprocating compressors, the connection piece is attached in the bottom part of the compressor housing also because the fully assembled, electrically operated piston pumps are inserted into the bottom part of the two-part compressor housing in a first step of the production process, and the electrical connection is thereby established via the connection piece with the electrical control unit. Subsequently, the cover of the compressor housing is attached and tightly welded to the bottom part of the housing. One way to avoid the disadvantages described above is to use an oblique dividing plane between the cover and the bottom part of the two-part housing. In this way, sufficient space can be created on the cover for attaching the connection piece. However, such a dividing plane leads to other disadvantages. For example, the production of an oblique dividing plane is associated with greater effort in terms of production technology in comparison to the production of a horizontal dividing line, since other production machines have to be used or, respectively, existing ones have to be converted and/or reprogrammed. In addition, problems arise with respect to the arrangement of the components of the refrigerant compressor, in particular the piston pump. Although the connection piece can be integrated into the cover of the housing compressor due to the oblique dividing line, there is a risk of the connection piece colliding with the electric piston pump. As a result, the housing parts are no longer hermetically sealable with one another.

There is therefore a need to provide a refrigerant compressor comprising a connection piece which avoids the above-mentioned disadvantages of the prior art.

The present invention achieves the given objects by providing a hermetically encapsulated refrigerant compressor of the reciprocating compressor type comprising a housing having a bottom part and a cover, the cover being connectable to the bottom part, an electrical connection piece penetrating the housing and a piston pump which is arranged in the housing and can be electrically connected to a control unit via the connection piece. The cover of the housing has a through opening in which the electrical connection piece is arranged. The housing is configured in such a way that, when the housing is open, the piston pump can be inserted into the cover of the housing and is connectable to the electrical connection piece.

Furthermore, the invention achieves the given object by means of a method of assembling a hermetically encapsulated refrigerant compressor having the above-described features, the method comprising the following steps:

providing a housing having a bottom part and a cover and comprising a through opening penetrating the cover;

sealingly inserting an electrical connection piece into the through opening of the housing;

placing the cover on a working surface with its open side up;

providing a piston pump and inserting the piston pump into the cover of the housing from above in an upside-down manner;

establishing an electrical connection between the electrical connection piece and the piston pump;

arranging the bottom part with its open side down and placing the bottom part thus arranged on the cover of the housing;

establishing a hermetically sealed connection between the bottom part and the cover of the housing, preferably by means of a welded joint.

The advantage of a piston pump that can be inserted into the cover of the housing is that very low overall heights can be achieved. This provides an important economic benefit as smaller refrigerant compressors are easier to transport and more versatile. In addition, due to the low overall height of the refrigerant compressor, housing material can be saved, as a result of which the production costs of the refrigerant compressor are reduced.

A further advantage of the invention is that a substantially spherical design of the housing is feasible. Such a design can bring about an improvement in the structural/mechanical properties of the compressor, or the compressor can thereby be designed according to structural/mechanical criteria. In addition, this design of the refrigerant compressor allows the housing to be downsized with the compression capacity remaining the same.

Another essential advantage of the invention is that cables which interconnect the reciprocating compressor and electrical add-on parts, in particular a control unit, can be connected to the cover of the housing. As a result, the electrical control unit can also be arranged in areas outside of the compressor housing which allow for simplified and easier installation of the compressor. In addition, the cable connections can be kept short, whereby the cables are prevented from lying on the base and the resulting risks of damage to the cables and short circuits are avoided.

According to an advantageous embodiment of the invention, the housing has a substantially horizontal dividing plane between the bottom part and the cover of the housing so that the cover and the bottom part can be easily welded along this dividing plane. In addition to the production being easier, the assembly and the hermetic sealing as a result of the cover and the bottom part being welded with a horizontal dividing plane involve less effort and can therefore be implemented faster than in the case of a compressor with an oblique dividing plane.

In a preferred embodiment, the piston pump according to the invention can be inserted into the cover in an upside-down manner by means of a positioning aid. As a result, the piston pump can be easily wired to the electrical connection piece arranged in the cover, for which only short connecting cables are required. In one embodiment, the at least one positioning aid is designed as a support for the piston pump, the support comprising geometric formations, such as projections or ribs, on the inside of the cover. In an additional or alternative embodiment, the positioning aid has geometric formations, such as projections or ribs, on the housing of the piston pump, which formations serve as supports on the inside of the cover when the piston pump is being inserted into the cover of the housing. In a further embodiment, the positioning aid comprises at least one element that can be inserted into the cover and serves as a support for the piston pump. The insert element can be configured in such a way that it is removed from the cover before the housing is closed, after the piston pump has been positioned.

In a preferred embodiment of the refrigerant compressor according to the invention, the electrical connection piece is an electrical plug with a steel base body, which comprises metallic conductor pins held by an electrically insulating material, preferably glass, with the electrical connection piece being inserted into the through opening of the cover and being sealingly connected to the circumference of the cover's through opening. As a result, a current feedthrough can be created that is hermetically sealed, has a high dielectric strength and withstands high pressure loads, but at the same time also creates a stable electrical connection.

In a preferred embodiment, the housing is made of a corrosion-resistant material, preferably metal or metal alloys, with the housing parts preferably being deep-drawn parts. As a result, complex shapes can be created without major technical effort, whereby various further processing steps can be reduced or simplified and production costs can be lowered.

In a preferred embodiment of the invention, the cover of the housing has connecting pipes, in particular a suction pipe, a pressure pipe and a maintenance pipe. The arrangement of the connecting pipes on the cover of the housing allows the refrigerant compressor to be installed at its place of use in a space-saving manner, whereby the refrigerating machines can be designed on a smaller and more compact scale.

In a preferred embodiment, the bottom part of the housing has adjustable feet or fastening elements on its outside.

The above-described method according to the invention of assembling a hermetically encapsulated refrigerant compressor provides the significant advantage that the electrical connection piece can be arranged in the cover of the housing, in contrast to refrigerant compressors according to the prior art, and the refrigerant compressor can nevertheless be assembled easily and in just a few steps, which is of great value for mass production. In particular, the piston pump, which is arranged in the cover, can easily be wired to the electrical connection piece. After the assembly has been completed, the external components, in particular an electrical control unit, can be quickly and easily connected to the refrigerant compressor by a skilled person. In addition, the control unit can be arranged, for example, on the outer area of the cover or in the vicinity thereof, in such a way that the assembly and installation of the refrigerant compressor can be performed faster. In doing so, cable connections can be kept very short and kinks in the cables can be avoided, since the cables are supplied to the electrical connection piece in the area of the cover.

Overall, the time required for producing, fitting and connecting the electrical connections of the refrigerant compressor can be significantly reduced by the present invention, and costs can be saved in the production of such refrigerant compressors.

The invention will now be explained in further detail on the basis of exemplary embodiments, with reference to the drawings.

FIG. 1 is a perspective view of a hermetically encapsulated refrigerant compressor comprising a connection piece according to the present invention.

FIG. 2 is a sectional view of the hermetically encapsulated refrigerant compressor of FIG. 1 .

Hereinafter, reference is made to FIGS. 1 and 2 . The invention provides a hermetically encapsulated refrigerant compressor 100 comprising a housing 10 having a bottom part 11 and a cover 12. The bottom part 11 and the cover 12 are each formed in the shape of a bowl. The cover 12 has a through opening 12 a into which an electrical connection piece 30 is inserted in a hermetically sealing manner. The electrical connection piece 30 can be connected to a control unit, which is not shown in the figures. A piston pump 40, which can be electrically connected to the control unit via the electrical connection piece 30, is arranged in the interior of the housing 10. The connection piece 30 comprises electrical plugs 31 with steel base bodies on its outside and its inside, the electrical plugs 31 comprising metallic conductor pins 32 held by an electrically insulating material, in particular glass. The electrical connection piece can be a conventional component.

The housing 10 of the refrigerant compressor 100 is formed from a die-cast metal or a metal alloy. As can be seen in the figures, the bottom part 11 has a substantially horizontal, weldable dividing plane 50 with the cover 12 of the housing 10. Furthermore, the cover 12 of the housing 10 contains connecting pipes 20, 21, 22, in particular a suction pipe 20, a pressure pipe 21 and a maintenance pipe 22.

The refrigerant compressor 100 has fastening elements 13, 14 on the bottom part 11 of the housing 10 so that it can be securely fixed to a base, for example, by means of a screw connection.

The steps of assembling the hermetically encapsulated refrigerant compressor 100 are illustrated below. Those steps comprise:

providing a housing 10 having a bottom part 11 and a cover 12 and comprising a through opening 12 a penetrating the cover 12;

sealingly inserting an electrical connection piece 30 into the through opening 12 a of the housing 10;

placing the cover 12 on a working surface with its open side, i.e., its underside, up;

providing a piston pump 40 and inserting the piston pump 40 into the cover 12 of the housing 10 from above in an inverted position, i.e., in an upside-down manner;

establishing an electrical connection between the electrical connection piece 30 and the piston pump 40;

arranging the bottom part 11 with its open side down, i.e., in an inverted position, and placing the bottom part 11 thus arranged on the cover 12 of the housing 10;

establishing a hermetically sealed connection between the bottom part 11 and the cover 12 of the housing 10, preferably by means of a welded joint.

The electrical connection of the piston pump 40 to the connection piece 30 is effected via cable lines, not shown, which are connected to those parts of the metal pins 32 which face the interior of the housing 10. By means of cables, a control unit for the piston pump 40 can be electrically connected to those parts of the metal pins 32 which protrude from the housing 10.

The piston pump 40 is inserted into the cover 12 of the housing 10 from above in an upside-down manner in such a way that the piston pump 40 will lie on defined positioning aids 12 b, 12 c of the cover 12. 

1-12. (canceled)
 13. A hermetically encapsulated refrigerant compressor comprising a housing having a bottom part and a cover, the cover being connectable to the bottom part, an electrical connection piece penetrating the housing and a piston pump which is arranged in the housing and can be electrically connected to a control unit via the connection piece, characterized in that the piston pump is arranged in the cover of the housing and the cover of the housing has a through opening in which the electrical connection piece is arranged and that the housing is configured in such a way that, when the housing is open, the piston pump can be inserted into the cover of the housing and is connectable to the electrical connection piece.
 14. A refrigerant compressor according to claim 13, characterized in that at least one positioning aid is provided onto which the piston pump can be attached in an upside-down manner, with the housing being open.
 15. A refrigerant compressor according to claim 14, characterized in that the positioning aid comprises geometric formations, such as projections or ribs, on the inside of the cover, the geometric formations serving as supports for the piston pump.
 16. A refrigerant compressor according to claim 14, characterized in that the positioning aid comprises geometric formations, such as projections or ribs, on the housing of the piston pump, which formations serve as supports on the inside of the cover when the piston pump is being inserted into the cover of the housing.
 17. A refrigerant compressor according to any of claims 14, characterized in that the positioning aid comprises at least one element insertable into the cover and serving as a support for the piston pump.
 18. A refrigerant compressor according to claim 13, characterized in that the electrical connection piece forms electrical plugs with a steel base body and metallic conductor pins held by an electrically insulating material, preferably glass, with the electrical connection piece being inserted into the through opening of the cover and being sealingly connected to the circumference of the cover's through opening.
 19. A refrigerant compressor according to claim 13, characterized in that the housing has a substantially horizontal dividing plane between the bottom part and the cover of the housing, whereby the bottom part and the cover of the housing can be welded together along this dividing plane.
 20. A refrigerant compressor according to claim 13, characterized in that the housing is made of a corrosion-resistant material, preferably metal or metal alloys, with the housing parts preferably being deep-drawn parts.
 21. A refrigerant compressor according to claim 13, characterized in that the cover of the housing has connecting pipes, in particular a suction pipe, a pressure pipe and a maintenance pipe.
 22. A refrigerant compressor according to claim 13, characterized in that the bottom part of the housing has adjustable feet or fastening elements on its outside.
 23. A method of assembling a hermetically encapsulated refrigerant compressor according to claim 13, the method comprising the following steps: providing a housing having a bottom part and a cover and comprising a through opening penetrating the cover; sealingly inserting an electrical connection piece into the through opening of the cover of the housing; placing the cover on a working surface with its open side up; providing a piston pump and inserting the piston pump into the cover of the housing from above in an upside-down manner; establishing an electrical connection between the electrical connection piece and the piston pump; arranging the bottom part with its open side down and placing the bottom part thus arranged on the cover of the housing; establishing a hermetically sealed connection between the bottom part and the cover of the housing, preferably by means of a welded joint.
 24. A method according to claim 23, characterized in that the piston pump is inserted into the cover of the housing from above in an upside-down manner in such a way that the piston pump will be oriented and will lie by means of at least one positioning aid. 